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Finding the Fourth Proportional to 105.49, 145.71 and 81.23

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Solution

The fourth proportional to 105.49, 145.71 and 81.23 is: 112.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    105.49 : 145.71 = 81.23 : x
  2. Step 2: Convert to fraction form
    105.49/145.71 = 81.23/x
  3. Step 3: Cross multiply
    105.49x = 145.71 × 81.23
  4. Step 4: Simplify right side
    105.49x = 11,835.29
  5. Step 5: Solve for x
    x = 11,835.29/105.49
  6. Step 6: Final answer
    x = 112.20

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.